What is the integral of e^(2x^2)e2x2?

1 Answer
Aug 3, 2015

int e^(2x^2) dx e2x2dx cannot be expressed using elementary functions. You need the imaginary error function, erfi(x).

Explanation:

The imaginary error function is 2/sqrtpi int e^(x^2) dx2πex2dx

int e^(2x^2) dx e2x2dx can be intergrated using substitution u = sqrt2 xu=2x so du = sqrt2 dxdu=2dx and we get:

int e^(2x^2) dx = 1/sqrt2 int e^(u^2) due2x2dx=12eu2du

= 1/sqrt2 sqrtpi/2 "erfi" u +C=12π2erfiu+C

= sqrt(2pi)/4 "erfi"(sqrt2x) +C=2π4erfi(2x)+C